다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

This paper completely introduces an exhaustive and a comprehensive review of the so-called salp swarm algorithm (SSA) and discussions its main characteristics. SSA is one of the efficient recent meta-heuristic optimization algorithms, where it has been successfully utilized in a wide range of optimization problems in different fields, such as machine learning, engineering design, wireless networking, image processing, and power energy. This review shows the available literature on SSA, including its variants, like binary, modifications and multi-objective. Followed by its applications, assessment and evaluation, and finally the conclusions, which focus on the current works on SSA, suggest possible future research directions.

Salp swarm algorithm: a comprehensive survey

The grasshopper optimization algorithm is one of the dominant modern meta-heuristic optimization algorithms. It has been successfully applied to various optimization problems in several fields, including engineering design, wireless networking, machine learning, image processing, control of power systems, and others. We survey the available literature on the grasshopper optimization algorithm, including its modifications, hybridizations, and generalization to the binary, chaotic, and multi-objective cases. We review its applications, evaluate the algorithms, and provide conclusions.

A comprehensive survey of the Grasshopper optimization algorithm: results, variants, and applications

This work endeavours to propose an approximate mathematical model of a community based renewable microgrid with solar photovoltaic, biogas and biodiesel generators including battery storage for load frequency studies. It becomes a great challenge to coordinate between generation and load demand of the microgrid as the renewable sources are highly unpredictable and nature dependent. To overcome this issue, the responses of the system are studied under different real-world scenarios of renewable source availabilities and load variations with a maiden approach towards optimising the controller gains using a recent grasshopper optimisation algorithm (GOA) for efficient frequency control. The frequency responses of proposed microgrid are compared with different conventional controllers and some popular optimisation algorithms using MATLAB/Simulink. Finally, proportional-integral-derivative controller with GOA is preferred for the case studies under four cases of source variations with step load perturbation and one case of simultaneous source and load variations. The results of all these five scenarios are found satisfactory in terms of frequency responses and reported in the work.

https://ietresearch.onlinelibrary.wiley.com/doi/pdf/10.1049/iet-rpg.2018.5196

Expeditious frequency control of solar photovoltaic/biogas/biodiesel generator based isolated renewable microgrid using grasshopper optimisation algorithm

Displacement of conventional synchronous generators by non-inertial units such as wind or solar generators will result in reduced-system inertia affecting under-frequency response. Frequency control is important to avoid equipment damage, load shedding, and possible blackouts. Wind generators along with energy storage systems can be used to improve the frequency response of low-inertia power system. This paper proposes a fuzzy-logic based frequency controller (FFC) for wind farms augmented with energy storage systems (wind-storage system) to improve the primary frequency response in future low-inertia hybrid power system. The proposed controller provides bidirectional real power injection using system frequency deviations and rate of change of frequency (RoCoF). Moreover, FFC ensures optimal use of energy from wind farms and storage units by eliminating the inflexible de-loading of wind energy and minimizing the required storage capacity. The efficacy of the proposed FFC is verified on the low-inertia hybrid power system.

Fuzzy-logic based frequency controller for wind farms augmented with energy storage systems

Analysis of GOA optimized two-stage controller for frequency regulation of grid integrated virtual power plant

This work is a maiden attempt towards the voltage stability enhancement of a hybrid power system (HPS) comprising of Parabolic Trough solar power (PSP), Dish-Stirling Solar Power (DSP) and diesel generator (DG). DSP coupled with induction generator requires reactive power for its field winding to be magnetized whereas PSP employing permanent magnet synchronous generator (PMSG) doesn’t require reactive power for excitation. So, it’s worthwhile to infer that PSP reduces the reactive power requirement for its own functionality and may meet the same load demand at low voltage compensation. Lower voltage compensation requirement results in higher voltage stability. Besides, dynamic responses of the system are also improved as the HPS has been incorporated with Voltage Compensating Devices (VCDs) like Static Var Compensator (SVC), Static Synchronous Compensator (STATCOM) and Dynamic Voltage Restorer (DVR). Inclusion of FACTS devices reduces the probability of the transient voltage instability. HPS with FACTS devices under PSP has been subjected to the critical change in load with positive and negative infinite slope at regular interval of time to see the system practicality and its feasibility. The graphical and numerical analysis of the proposed system explicitly shows that the proposed HPS with PSP retains the system voltage stability with great margin under DVR. The efficient hybrid power system as a whole has been achieved to maintain the system reliability in terms of voltage because of the presence of PSP and DVR.

/pdf/maiden-voltage-control-analysis-of-hybrid-power-system-with-3nzad0zv1c.pdf

Maiden Voltage Control Analysis of Hybrid Power System With Dynamic Voltage Restorer

This work is an early attempt to study the frequency fluctuations because of penetration of Wind and Solar-thermal based renewable powers into a demand response supported isolated hybrid microgrid, coordinating Micro-hydro/Biogas/Biodiesel generators using Fuzzy Proportional, derivative+Integral (PD+I) controller. Initially, a fuzzy PD+I controller is designed considering 5 membership functions and the proposed system responses are compared with PID and fuzzy PD controllers by tuning gains considering the same parameters of particle swarm optimization (PSO). The responses of the proposed microgrid are investigated by connecting renewable units one by one with the Biogas/micro-hydro generator, which witness the increment in fluctuations with penetration. Finally, frequency fluctuations of the system are adequately reduced optimally by the inclusion of Biodiesel generator and demand response contributions into the microgrid using PSO tuned Fuzzy PD+I controllers.

Optimal Load-Frequency Regulation of Demand Response Supported Isolated Hybrid Microgrid Using Fuzzy PD+I Controller

The article assesses the frequency control of a dual area hybrid microgrid (DHM) that comprises solar thermal systems alongside biodiesel-powered generators, energy storage components, and DC link. The chaotic butterfly optimization (CBOA) technique is used to attain the tuned gain constraints of the cascaded PI-TID controller. The novelty of the system lies in the integration of a combined solar gas turbine and solar chimney for load frequency control studies. Also, the application of CBOA to tune the controllers of cascaded PI-TID controllers is a novel approach. The superiority of CBOA tuned PI-TID controller is obtained after performing a comparative analysis of PID, TID, and PI-TID for controller selection and PSO, SCA, BOA, and CBOA for selecting the superior algorithm. The outcome of each component of the system is analyzed and subjected to the consideration of different real-time scenarios. Sensitivity evaluation is carried out by altering the source and load settings to establish the domination of the CBOA optimized PI-TID controller. 

Dulal Chandra Das

Papers

Analysis of GOA optimized two-stage controller for frequency regulation of grid integrated virtual power plant

Maiden Voltage Control Analysis of Hybrid Power System With Dynamic Voltage Restorer

Optimal Load-Frequency Regulation of Demand Response Supported Isolated Hybrid Microgrid Using Fuzzy PD+I Controller

Performance Assessment of Novel Solar Thermal-Based Dual Hybrid Microgrid System Using CBOA Optimized Cascaded PI-TID Controller

Active power control of autonomous hybrid power system using two degree of freedom PID controller